Here is the situation. Visibility is 48. All hexes involved are level 0 and in a row left to right. Suppression level of friendly units is 1.
There is a light smoke hex. Friendly units one and two hexes to the left of the smoke hex can see an enemy four hexes to the right of the smoke hex, but a friendly unit four hexes to the left cannot.
How does smoke affect sighting such that units close to the smoke can see through it but farther ones can't? If there were enemy units closer to the smoke, would the leftmost unit have seen them?
This has been covered at least once before with you. There are other hindrance effects in play quite possibly invisible smoke. As hindrance is cumulative the los becomes blocked.
Look at it this this way when concidering smoke cover.
There is no border,it flows with the wind,mainly NE,but can effect adjecent hexs too,depending on your LOS.
Smoke can be a double-eged sword though.
It does disperse in time,and if used at the right time it(wether which side uses it)to hide,ambush or attack